Microwave detection up to 43.5 GHz by GaN nanodiodes: Experimental and analytical responsivity

Abstract

Planar nano-diodes fabricated on an AlGaN/GaN heterolayer have been measured, showing capability to detect microwave signals up to 43.5 GHz at room temperature. A single nano-diode with length L=1000 nm and width W=74 nm provides a response of approximately 55 mV DC output for a 0 dBm nominal input power at 1 GHz, with a very small fraction of the RF power reaching effectively the device due to a very large impedance mismatch. A comprehensive analytical study, which uses as input data just the measured DC current-voltage curve of the diodes, is able to replicate the values of the RF characterization and allows a deep understanding of the detection mechanism.

Microwave Detection Using Two-Atom-Thick Self-Switching Diodes Based on Quantum Simulations and Advanced Circuit Models

“…However, in the last years, the attention has been moving toward geometrical diodes [1], that is, diodes which are created by etching channels in a planar semiconductor/semimetal. These devices are called "self-switching diodes" (SSDs), which have been demonstrated to detect both microwaves [2]- [4] and terahertz signals [5]- [7]. An SSD is different from classical diodes, in the sense that no junctions are necessary (hence, no doping), and its physics relies upon a nonlinear current, which flows through nanometer-sized parallel channels and is controlled by field-effect phenomena.…”

Voltage controlled sub-THz detection with gated planar asymmetric nanochannels

“…This quasi-static model has been satisfactorily used to analyze the performance of RF detectors based on SSDs made on InAs 5 and GaN. 21 By means of a polynomial fitting of order three (using 20 points within the [À0.1 V, þ0.1 V] range), the values of (i) the resistance, R, and (ii) the bowing coefficient, defined as c ¼…”

“…Figure 5(a) also shows the values of b obtained in ungated SSDs. 7,8,20,21 Interestingly, the value of the responsivity of the G-SSD overcomes that of ungated SSDs when entering the near pinch-off gate bias region (DV < 0.5 V). This is also an evidence that under those conditions, an additional current control mechanism is in action.…”

High-frequency response and thermal effects in GaN diodes and transistors: modeling and experimental characterization

“…As it was explained in the introduction, surface charges at the walls deplete the channel. At equilibrium, the surface charges produce a depletion region near the interfaces of about 30 nm at each side of the channel, value determined by the method that will be explained in subsection 2.3.3, based on resistance measurements of SSDs with dierent widths [97]. Since the channel width in this channel is W = 75 nm, it is near to be completely depleted, its current level is low and the inuence of the occupancy of surface states is very strong, since they modify quite noticeably the width of the conducting channel.…”